Effect of flaxseed supplementation on markers of inflammation and endothelial function: A systematic review and meta-analysis

Askarpour, Moein; Karimi, Mohammadreza; Hadi, Amir; Ghaedi, Ehsan; Symonds, Micheal E.; Miraghajani, Maryam; Javadian, Parisa

doi:10.1016/j.cyto.2019.154922

Cited by 35 publications

(31 citation statements)

References 68 publications

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“…The lack of apparent effect of flaxseed on triglycerides may also be associated with a wide range of concentrations seen in our small group of patients. We also did not record any significant effect of flaxseed on biochemical parameters of inflammation, which is in contrast to some studies showing a significant reduction in CRP and IL-6 levels [30,31]. On the other hand, other reports also did not detect significant changes in IL-6 and TNFα in response to PUFA-rich diets [32].…”

Section: Discussioncontrasting

confidence: 99%

Flaxseed (Linum Usitatissimum L.) Supplementation in Patients Undergoing Lipoprotein Apheresis for Severe Hyperlipidemia—A Pilot Study

et al. 2020

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Being rich in polyunsaturated fatty acids, flaxseed (Linum usitatissimum L.) is thought to be able to decrease lipid levels and dampen inflammation. In this pilot study, we aimed to determine whether flaxseed supplementation could improve the profiles of lipids and inflammatory mediators in patients with severe hyperlipidemia resistant to conventional lipid-lowering pharmacotherapy and requiring lipoprotein apheresis. To this end, six patients received, blindly—in addition to their normal lipoprotein apheresis regimen—a 10-week dietary supplementation with flaxseed (28 g/d) administered in biscuits. This was followed by a 10-week washed out-period and a 10-week supplementation phase with whole wheat placebo. Blood samples were collected at the end of each phase, before the lipoprotein apheresis session. The primary endpoint was the lipid profile and the secondary endpoints were the concentrations of inflammatory mediators and tolerability. Flaxseed supplementation was well-tolerated and resulted in a consistent and significant decrease in total cholesterol and low-density lipoprotein (LDL) levels. The median (and range) percentage decrease was 11.5% (0–18.8) and 7.3% (4.4–26.6), for cholesterol (p = 0.015) and LDL-C (p = 0.003), respectively. On the other hand, there was no significant effect of flaxseed on lipoprotein(a) (Lp(a)), C-reactive protein (CRP), and interleukin 6 (IL-6) concentrations. These observations indicate that flaxseed can produce a cholesterol- and LDL-lowering effect in patients treated with lipoprotein apheresis. Thus, flaxseed supplementation may help to control cholesterol in this patient population. The flaxseed supplementation protocol applied may be of use for further adequately-powered studies to validate and extend our findings.

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Section: Discussioncontrasting

confidence: 99%

Flaxseed (Linum Usitatissimum L.) Supplementation in Patients Undergoing Lipoprotein Apheresis for Severe Hyperlipidemia—A Pilot Study

et al. 2020

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“…Previous meta-analysis assessed the effects of flaxseed and flaxseed-derived products (flaxseed oil or lignans) on inflammatory cytokines, did not reach consistent conclusions [ 15 , 80 , 81 ]. The present meta-analysis indicated that flaxseed supplementation significantly decreased IL-6, rather not CRP, hs-CRP and TNF-α.…”

Section: Discussionmentioning

confidence: 99%

Comparisons of the effects of different flaxseed products consumption on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases: systematic review and a dose–response meta-analysis of randomized controlled trials

et al. 2021

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Background Flaxseed is widely used as a functional food for its rich sources of linolenic acid, lignans and dietary fibers in the world. This systematic review and dose–response meta-analysis on randomized controlled trials (RCTs) is first to evaluate effects of different flaxseed products (whole flaxseed, oil and lignans) on lipid profiles, inflammatory and anthropometric parameters in patients with dyslipidemia related diseases. Methods Literature search was performed in PubMed, Embase, Cochrane Central, Scopus, and Web of Science from the inception dates to January, 2020. Weighted mean differences with the 95% confidence interval (CI) were pooled using fix or random-effects models. Results Thirty-one RCTs involving 1,698 participants were included. The present meta-analysis revealed that flaxseed consumption had an overall beneficial effect on serum TC, LDL-C, TG, apo B and IL-6 in patients with dyslipidemia related diseases, but not on apo A, HDL-C, hs-CRP, CRP and anthropometric indices. However, different flaxseed products showed obviously different effects. Whole flaxseed supplementation significantly reduced TC (− 11.85 mg/dl, 95% CI − 20.12 to − 3.57, P = 0.005), LDL-C (− 10.51 mg/dl, 95% CI − 14.96 to − 6.06, P < 0.001), TG (− 19.77 mg/dl, 95% CI − 33.61 to − 5.94, P = 0.005), apolipoprotein B (− 5.73 mg/dl, 95% CI − 7.53 to − 3.93, P < 0.001), TC/HDL-C (− 0.10, 95% CI − 0.19 to − 0.003, P = 0.044) and weight (− 0.40 kg, 95% CI − 0.76 to − 0.05, P = 0.027); Lignans supplementation significantly reduced TC (− 17.86 mg/dl, P = 0.004), LDL-C (− 15.47 mg/dl, P < 0.001) and TC/HDL-C (− 0.45, P = 0.04). Although flaxseed oil supplementation had no such lowering-effect on lipid, meta-analysis revealed its lowering-effect on IL-6 (− 0.35 pg/ml, P = 0.033) and hs-CRP (− 1.54 mg/l, P = 0.004). Subgroup analysis revealed that whole flaxseed decreased TC, LDL-C and TG levels irrespective of country and the intervention time prescribed, but was more pronounced when the dose of whole flaxseed was ≤ 30 g/day (TC: WMD − 13.61 mg/mL; LDL-C: WMD − 10.52 mg/mL; TG: WMD − 23.52 mg/mL), rather not a dose > 30 g/day. Moreover, a linear relationship between dose of whole flaxseed and absolute changes in C-reactive protein (P = 0.036) and a nonlinear relationship between with IL-6 (P < 0.001) were detected. Conclusions Flaxseed intervention suggested the positive effects on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases. Of these, whole flaxseed and lignans play an important role in reducing blood lipid, while flaxseed oil mainly plays in anti-inflammatory. Lipid- and weight-lowering was significant when whole flaxseed was consumed at doses < 30 mg/d, for lipid status with mixed dyslipidemia and patients with BMI > 25. Graphic abstract

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“…47 Scientists proposed that this beneficial effect may be mediated by an effect on inflammatory mediators because of different mechanisms such as interaction with oestrogen receptors, the inhibition of tyrosine kinase, antioxidant effects 48 and a reduction in gene expression of inflammatory mediators via the modulation of nuclear factor-ĸB (NF-ĸB) pathway. [49][50][51][52][53] Genistein as a natural selective oestrogen receptor (ER) modulator and antioxidant is the most important soy isoflavones that affects positively cardiovascular system. 54 Because in animal studies, oestrogen therapy has been indicated…”

Section: Discussionmentioning

confidence: 99%

The efficacy of soy isoflavones combined with soy protein on serum concentration of interleukin‐6 and tumour necrosis factor‐α among post‐menopausal women? A systematic review and meta‐analysis of randomized controlled trials

Gholami

Mollanoroozy

Baradaran

et al. 2021

Clin Exp Pharma Physio

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The post-menopausal stage in women's life is associated with the enhancement of inflammation that may be reduced using soy isoflavones or soy protein. The present study aimed to summarize the effect of soy isoflavones plus soy protein on circulating interleukin-6 (IL-6) and tumour necrosis factorα (TNFα) in post-menopausal women.The English-language articles were identified from the databases such as Cochrane Library, clinicaltrials.gov, Web of Science, PubMed, and Scopus until December 2020.The mean change from baseline and its standard deviation (SD) for intervention and comparison groups were used to calculate the effect size. The statistical heterogeneity of the intervention effects was computing by Cochran's Q test and I 2 statistic. Nine and seven studies were selected for systematic review and meta-analysis, respectively. The results of our meta-analysis indicated a non-significant effect on the serum concentrations of IL-6 and TNFα (weighted mean differences [WMD] = 0.07 pg/mL; 95% confidence interval [CI] = −0.03, 0.17 pg/mL; P = 0.190; WMD =0.05 pg/mL; 95% CI = −0.01, 0.12 pg/mL; P = 0.092; respectively). In subgroup analysis, soy isoflavones plus soy protein could increase the serum concentration of IL-6 in studies with soy isoflavones dose ≤87 mg/days, cross-over design, weak quality, and studies on participants who had health risk factors or diseases. The serum concentration of TNFα increased in studies with cross-over design, intervention duration ≤56 days, and body mass index (BMI) >27, and in studies that were conducted on at-risk or sick participants. In conclusion, our meta-analysis did not confirm any significant effect on serum concentration of IL-6 and TNFα among post-menopausal women.

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Effect of flaxseed supplementation on markers of inflammation and endothelial function: A systematic review and meta-analysis

Cited by 35 publications

References 68 publications

Flaxseed (Linum Usitatissimum L.) Supplementation in Patients Undergoing Lipoprotein Apheresis for Severe Hyperlipidemia—A Pilot Study

Flaxseed (Linum Usitatissimum L.) Supplementation in Patients Undergoing Lipoprotein Apheresis for Severe Hyperlipidemia—A Pilot Study

Comparisons of the effects of different flaxseed products consumption on lipid profiles, inflammatory cytokines and anthropometric indices in patients with dyslipidemia related diseases: systematic review and a dose–response meta-analysis of randomized controlled trials

The efficacy of soy isoflavones combined with soy protein on serum concentration of interleukin‐6 and tumour necrosis factor‐α among post‐menopausal women? A systematic review and meta‐analysis of randomized controlled trials

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